Process for treating composite chromium plating layer of barrel inner bore

Abstract

The invention relates to the technical field of chromium plating, in particular to a barrel inner bore composite chromium plating layer treatment process which comprises the following steps: S1, pretreatment; s2, glow cleaning; s3, carrying out first multi-arc ion plating; s4, performing pulse etching; s5, secondary multi-arc ion plating is carried out; and S6, cooling and discharging. The Cr coating is prepared on the surface of the barrel inner bore through the multi-arc ion plating technology, the abrasion resistance of the barrel inner bore is remarkably improved, abrasion in the shooting process is effectively reduced, the oxidation resistance of the barrel inner bore is remarkably improved, and the service life of the barrel is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of chrome plating, in particular to a process for treating a composite chrome plating layer in a barrel inner bore. Background Art

[0002] The barrel is a core component of light weapons. Due to the high temperature, high pressure and strong friction in the service environment of its inner bore, the performance of the barrel base material itself cannot meet its comprehensive performance requirements. The existing technology often uses a chrome plating process to plate a certain thickness of chrome layer on the surface of its inner bore to achieve the purpose of corrosion resistance, wear resistance and low friction, and ultimately extend the comprehensive life of light weapons.

[0003] Since the chrome layer is formed inside the barrel, the traditional immersion chrome plating process is difficult to control the quality when processing the inner bore of a slender barrel. This may lead to significant longitudinal non-uniformity of the chrome layer (such as taper difference), rough crystal structure and insufficient surface finish. These factors work together to reduce the pass rate of one-time chrome plating of the inner bore of a slender barrel. Summary of the invention

[0004] The object of the present invention is to provide a composite chromium plating treatment process for the inner bore of a barrel to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a process for treating a composite chromium plating layer on the inner bore of a barrel, comprising the following steps:

[0006] S1. Pretreatment: First, use anhydrous ethanol to ultrasonically clean the barrel for 20 to 30 minutes, then wipe the barrel with anhydrous ethanol, and finally dry it, repeating twice;

[0007] S2. Glow cleaning: First, place the barrel in the vacuum chamber of the magnetron sputtering ion coating machine, evacuate to 2.0×10^(-3)Pa, then heat the barrel to 300-320℃, and fill the vacuum chamber with argon gas to 0.3-1.0Pa, then add a negative bias voltage of 500V to the inner bore of the barrel, and increase it to 900V within 2-3min, and finally bombard the inner bore of the barrel with argon ions for 10-20min;

[0008] S3, first multi-arc ion plating: fill the vacuum chamber with argon gas to 2-5 Pa, apply a negative bias voltage of 300-450 V to the inner bore of the barrel, apply an arc current of 60-90 A to the chromium target, and control the chromium target to enter the inner bore of the barrel evenly along the axial direction, deposit for 20-30 minutes, and plate the first chromium layer on the inner bore of the barrel;

[0009] S4, pulse etching: select ultrashort pulse laser, set the laser pulse width to 100-300 femtoseconds, and the laser energy density to 0.5-1.5 J / cm 2, and set the rotation speed of the ultrashort pulse laser to 10-30rpm, the moving speed of the ultrashort pulse laser along the axis direction to 1-5mm / s, first control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to enter the inner bore of the barrel, and then control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to exit the inner bore of the barrel;

[0010] S5. Second multi-arc ion plating: fill the vacuum chamber with argon gas to 2-5 Pa, apply a negative bias voltage of 500-900 V to the inner bore of the barrel, apply an arc current of 100-120 A to the chromium target, and control the chromium target to uniformly enter the inner bore of the barrel along the axial direction, deposit for 30-60 minutes, and plate the second chromium layer on the first chromium layer;

[0011] S6, cooling and taking out of the furnace: first gradually reduce the negative bias voltage and arc current, then restore the normal pressure of the vacuum chamber, and take out the barrel after it cools to room temperature.

[0012] Optionally, the barrel material is PCrNi3MoVA.

[0013] Optionally, the thickness of the first chromium layer and the second chromium layer are equal, and are both 25-50 μm, and the etching depth of the ultrashort pulse laser on the surface of the first chromium layer is 100-200 nm.

[0014] Optionally, the etching diameter of the ultrashort pulse laser is 1-2 μm, and the laser focal length accuracy of the ultrashort pulse laser is ±0.5 μm.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention adopts multi-arc ion plating technology to prepare a Cr coating on the surface of the barrel inner bore, which significantly improves the wear resistance of the barrel inner bore, effectively reduces the wear during shooting, and significantly improves the oxidation resistance of the barrel inner bore, prolongs the service life of the barrel, and the Cr coating effectively isolates the contact between the corrosive medium and the gun steel matrix, and reduces the corrosive ions in the residual chamber;

[0017] 2. The present invention uses an ultrashort pulse laser to enter and exit the inner bore of the barrel in a clockwise direction along the axial direction to etch two intersecting spiral etching grooves on the first chromium layer. The second chromium layer will fill the spiral etching grooves when deposited on the first chromium layer. Therefore, the intersecting spiral etching grooves can increase the contact area and bonding strength between the first chromium layer and the second chromium layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the SEM morphology of Example 4 in Experimental Example 2;

[0019] Figure 2 for Figure 1 The SEM morphology of the central area in the image is magnified 2000 times;

[0020] Figure 3 for Figure 2 EDS analysis of region A in center. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Embodiment 1: The present invention provides a process for treating a composite chromium plating layer on the inner bore of a barrel, comprising the following steps:

[0023] S1. Pretreatment: First, use anhydrous ethanol to ultrasonically clean the barrel for 20 minutes, then wipe the barrel with anhydrous ethanol, and finally dry it, repeating twice;

[0024] S2. Glow cleaning: First, place the barrel in the vacuum chamber of the magnetron sputtering ion coating machine, evacuate to 2.0×10^(-3)Pa, then heat the barrel to 300℃, and fill the vacuum chamber with argon gas to 0.3Pa, then add a negative bias voltage of 500V to the inner bore of the barrel, and increase it to 900V within 2min, and finally bombard the inner bore of the barrel with argon ions for 10min;

[0025] S3, first multi-arc ion plating: fill the vacuum chamber with argon gas to 2Pa, apply a negative bias voltage of 300V to the inner bore of the barrel, apply an arc current of 60A to the chromium target, and control the chromium target to enter the inner bore of the barrel evenly along the axial direction, deposit for 20 minutes, and plate a first chromium layer with a thickness of 25μm on the inner bore of the barrel;

[0026] S4, pulse etching: select ultrashort pulse laser, set the laser pulse width to 100 femtoseconds, and the laser energy density to 0.5J / cm 2 , and set the rotation speed of the ultrashort pulse laser to 10rpm, the moving speed of the ultrashort pulse laser along the axis direction to 1mm / s, first control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to enter the barrel inner bore, and then control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to exit the barrel inner bore;

[0027] S5. Second multi-arc ion plating: fill the vacuum chamber with argon gas to 2Pa, apply a negative bias voltage of 500V to the inner bore of the barrel, apply an arc current of 100A to the chromium target, and control the chromium target to enter the inner bore of the barrel evenly along the axial direction, deposit for 30 minutes, and plate a second chromium layer with a thickness of 25μm on the first chromium layer;

[0028] S6, cooling and taking out of the furnace: first gradually reduce the negative bias voltage and arc current, then restore the normal pressure of the vacuum chamber, and take out the barrel after it cools to room temperature.

[0029] Embodiment 2: The present invention provides a process for treating a composite chromium plating layer on the inner bore of a barrel, comprising the following steps:

[0030] S1. Pretreatment: First, use anhydrous ethanol to ultrasonically clean the barrel for 25 minutes, then wipe the barrel with anhydrous ethanol, and finally dry it, repeating twice;

[0031] S2. Glow cleaning: First, place the barrel in the vacuum chamber of the magnetron sputtering ion coating machine, evacuate to 2.0×10^(-3)Pa, then heat the barrel to 310℃, and fill the vacuum chamber with argon gas to 0.5Pa, then add a negative bias voltage of 500V to the inner bore of the barrel, and increase it to 900V within 2 minutes, and finally bombard the inner bore of the barrel with argon ions for 15 minutes;

[0032] S3, first multi-arc ion plating: fill the vacuum chamber with argon gas to 3Pa, apply a negative bias voltage of 350V to the inner bore of the barrel, apply an arc current of 70A to the chromium target, and control the chromium target to enter the inner bore of the barrel evenly along the axial direction, deposit for 25 minutes, and plate a first chromium layer with a thickness of 30μm on the inner bore of the barrel;

[0033] S4, pulse etching: select ultrashort pulse laser, set the laser pulse width to 150 femtoseconds, and the laser energy density to 1.05J / cm 2 , and set the rotation speed of the ultrashort pulse laser to 25rpm, the moving speed of the ultrashort pulse laser along the axis direction to 2mm / s, first control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to enter the barrel inner bore, and then control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to exit the barrel inner bore;

[0034] S5. Second multi-arc ion plating: fill the vacuum chamber with argon gas to 3Pa, apply a negative bias voltage of 700V to the inner bore of the barrel, apply an arc current of 110A to the chromium target, and control the chromium target to uniformly enter the inner bore of the barrel along the axial direction, deposit for 40 minutes, and plate a second chromium layer with a thickness of 30μm on the first chromium layer;

[0035] S6, cooling and taking out of the furnace: first gradually reduce the negative bias voltage and arc current, then restore the normal pressure of the vacuum chamber, and take out the barrel after it cools to room temperature.

[0036] Embodiment 3: The present invention provides a process for treating a composite chromium plating layer on the inner bore of a barrel, comprising the following steps:

[0037] S1. Pretreatment: First, use anhydrous ethanol to ultrasonically clean the barrel for 28 minutes, then wipe the barrel with anhydrous ethanol, and finally dry it, repeating twice;

[0038] S2. Glow cleaning: First, place the barrel in the vacuum chamber of the magnetron sputtering ion coating machine, evacuate to 2.0×10^(-3)Pa, then heat the barrel to 315℃, and fill the vacuum chamber with argon gas to 0.8Pa, then add a negative bias voltage of 500V to the inner bore of the barrel, and increase it to 900V within 3 minutes, and finally bombard the inner bore of the barrel with argon ions for 18 minutes;

[0039] S3, first multi-arc ion plating: fill the vacuum chamber with argon gas to 3Pa, apply a negative bias voltage of 400V to the inner bore of the barrel, apply an arc current of 80A to the chromium target, and control the chromium target to enter the inner bore of the barrel evenly along the axial direction, deposit for 28 minutes, and plate a first chromium layer with a thickness of 40μm on the inner bore of the barrel;

[0040] S4, pulse etching: select ultrashort pulse laser, set the laser pulse width to 200 femtoseconds, and the laser energy density to 1.2J / cm 2 , and set the rotation speed of the ultrashort pulse laser to 25rpm, the moving speed of the ultrashort pulse laser along the axis direction to 4mm / s, first control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to enter the barrel inner bore, and then control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to exit the barrel inner bore;

[0041] S5. Second multi-arc ion plating: fill the vacuum chamber with argon gas to 4 Pa, apply a negative bias voltage of 800 V to the inner bore of the barrel, apply an arc current of 115 A to the chromium target, and control the chromium target to uniformly enter the inner bore of the barrel along the axial direction, deposit for 50 minutes, and plate a second chromium layer with a thickness of 40 μm on the first chromium layer;

[0042] S6, cooling and taking out of the furnace: first gradually reduce the negative bias voltage and arc current, then restore the normal pressure of the vacuum chamber, and take out the barrel after it cools to room temperature.

[0043] Embodiment 4: The present invention provides a process for treating a composite chromium plating layer on the inner bore of a barrel, comprising the following steps:

[0044] S1. Pretreatment: First, use anhydrous ethanol to ultrasonically clean the barrel for 30 minutes, then wipe the barrel with anhydrous ethanol, and finally dry it, repeating twice;

[0045] S2. Glow cleaning: First, place the barrel in the vacuum chamber of the magnetron sputtering ion coating machine, evacuate to 2.0×10^(-3)Pa, then heat the barrel to 320℃, and fill the vacuum chamber with argon gas to 0.3~1.0Pa, then add a negative bias voltage of 500V to the inner bore of the barrel, and increase it to 900V within 3min, and finally bombard the inner bore of the barrel with argon ions for 20min;

[0046] S3, first multi-arc ion plating: fill the vacuum chamber with argon gas to 5Pa, apply a negative bias voltage of 450V to the inner bore of the barrel, apply an arc current of 90A to the chromium target, and control the chromium target to enter the inner bore of the barrel evenly along the axial direction, deposit for 30 minutes, and plate a first chromium layer with a thickness of 50μm on the inner bore of the barrel;

[0047] S4, pulse etching: select ultrashort pulse laser, set the laser pulse width to 300 femtoseconds, and the laser energy density to 1.5J / cm 2 , and set the rotation speed of the ultrashort pulse laser to 30rpm, the moving speed of the ultrashort pulse laser along the axis direction to 5mm / s, first control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to enter the inner bore of the barrel, and then control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to exit the inner bore of the barrel;

[0048] S5. Second multi-arc ion plating: fill the vacuum chamber with argon gas to 5 Pa, apply a negative bias voltage of 900 V to the inner bore of the barrel, apply an arc current of 120 A to the chromium target, and control the chromium target to uniformly enter the inner bore of the barrel along the axial direction, deposit for 60 minutes, and plate a second chromium layer with a thickness of 50 μm on the first chromium layer;

[0049] S6, cooling and taking out of the furnace: first gradually reduce the negative bias voltage and arc current, then restore the normal pressure of the vacuum chamber, and take out the barrel after it cools to room temperature.

[0050] In Examples 1 to 4, the material of the barrel is PCrNi3MoVA, and the laser focal length accuracy of the ultrashort pulse laser is ±0.5 μm; in Examples 1 and 2, the etching diameter of the ultrashort pulse laser is 1 μm, and in Examples 3 and 4, the etching diameter of the ultrashort pulse laser is 2 μm.

[0051] Test Example 1

[0052] Test content: The hardness test was conducted using a HTV-PHS30 high temperature Vickers hardness tester. During the test, the hardness tester host was placed in an inert gas protected atmosphere chamber to prevent the sample from being oxidized by high temperature. Then, a high temperature furnace was used to heat the sample to the required temperature and measure the hardness. First, a barrel without chrome plating was taken as a control group. The control group and the barrels obtained in Examples 1 to 4 were placed in the atmosphere chamber, and then filled with nitrogen. Then, the temperature was set to room temperature, 300°C, 500°C, and 700°C, respectively. Finally, the hardness at different temperatures was measured, and the results were recorded in Table 1.

[0053] Table 1

[0054]

[0055] As shown in Table 1, the hardness of the barrels obtained in Examples 1 to 4 decreases slowly compared to the barrels without chrome plating, especially at 700°C, the hardness of the barrels obtained in Examples 1 to 4 is much higher than that of the barrels without chrome plating, indicating that the chromium layer of the barrel inner bore obtained in Examples 1 to 4 has good resistance to scratches and wear, and good wear resistance. Therefore, the chromium layer of the barrel obtained in Examples 1 to 4 has good high-temperature mechanical properties and can meet the higher temperature environment of the inner bore. Among them, Example 4 has the highest hardness at various temperatures and is worthy of promotion and use.

[0056] Test Example 2

[0057] Test content: The barrel obtained in Example 4 is made into a gun steel matrix, and a copper rod with the same composition as the ammunition belt is selected as the friction pair. A simulated wear test of the inner wall of the barrel is established by a high-temperature and high-speed friction and wear machine. The reciprocating speed is set to 600r / min, the reciprocating length is 10mm, the loading load is 100N, and the friction time is 20min. Before the experiment, the temperature of the gun steel matrix needs to be heated to 300℃.

[0058] See also Figures 1 to 3 It can be seen that the material at point A is rich in elements O, Cu and Fe, including 2.97% Cu, 40.96% O and 41.60% Fe, which is mainly the oxidation of Fe and Cu. Therefore, the friction surface of the gun steel matrix is ​​mainly dominated by oxidation wear. The Cu element on the surface will be carried away or oxidized under the load pressure, so the copper hanging phenomenon is not obvious. The gun steel matrix has low adhesion to copper, which reduces the formation of copper deposition.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite chromium plating process for the inner bore of a barrel, characterized in that: The following steps are involved: S1. Pretreatment: First, use anhydrous ethanol to ultrasonically clean the barrel for 20 to 30 minutes, then wipe the barrel with anhydrous ethanol, and finally dry it, repeating twice; S2. Glow cleaning: First, place the barrel in the vacuum chamber of the magnetron sputtering ion coating machine, evacuate to 2.0×10^(-3)Pa, then heat the barrel to 300-320℃, and fill the vacuum chamber with argon gas to 0.3-1.0Pa, then add a negative bias voltage of 500V to the inner bore of the barrel, and increase it to 900V within 2-3min, and finally bombard the inner bore of the barrel with argon ions for 10-20min; S3, first multi-arc ion plating: fill the vacuum chamber with argon gas to 2-5 Pa, apply a negative bias voltage of 300-450 V to the inner bore of the barrel, apply an arc current of 60-90 A to the chromium target, and control the chromium target to enter the inner bore of the barrel evenly along the axial direction, deposit for 20-30 minutes, and plate the first chromium layer on the inner bore of the barrel; S4, pulse etching: select ultrashort pulse laser, set the laser pulse width to 100-300 femtoseconds, and the laser energy density to 0.5-1.5 J / cm 2 , and set the rotation speed of the ultrashort pulse laser to 10-30rpm, the moving speed of the ultrashort pulse laser along the axis direction to 1-5mm / s, first control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to enter the inner bore of the barrel, and then control the ultrashort pulse laser to rotate evenly clockwise along the axis direction to exit the inner bore of the barrel; S5. Second multi-arc ion plating: fill the vacuum chamber with argon gas to 2-5 Pa, apply a negative bias voltage of 500-900 V to the inner bore of the barrel, apply an arc current of 100-120 A to the chromium target, and control the chromium target to uniformly enter the inner bore of the barrel along the axial direction, deposit for 30-60 minutes, and plate the second chromium layer on the first chromium layer; S6, cooling and taking out of the furnace: first gradually reduce the negative bias voltage and arc current, then restore the normal pressure of the vacuum chamber, and take out the barrel after it cools to room temperature.

2. A barrel inner bore composite chromium plating treatment process according to claim 1, characterized in that: The material of the barrel is PCrNi3MoVA.

3. The process for treating the inner bore of a barrel with a composite chromium plating layer according to claim 1, characterized in that: The thickness of the first chromium layer and the second chromium layer are equal and are both 25-50 μm. The etching depth of the ultrashort pulse laser on the surface of the first chromium layer is 100-200 nm.

4. A barrel inner bore composite chromium plating treatment process according to claim 3, characterized in that: The etching diameter of the ultrashort pulse laser is 1 to 2 μm, and the laser focal length accuracy of the ultrashort pulse laser is ±0.5 μm.

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